1. Field of the Invention
The present invention relates to a recording apparatus having a function for copying an original document and a function for printing stored text and other image data. The copying operation is generally performed by projecting image light from the original document on a photoconductive member whereas the printing operation is generally performed by selectively exposing the photoconductive member based on an electric signal.
2. Description of the Prior Art
While a recording apparatus has as its basic function the duplication of an original document by an electrophotographic process, the recent trend in such apparatus is towards multiple functionality. One such function is operation as a printer, examples of which include laser beam printers and liquid crystal printers in which the processes used in document duplication are used in common with the printing operation after formation of a latent image on a photoconductive member.
When a document is copied on the above-described conventional recording apparatus, an exposure lamp is held on while a copying optical system and an original table are moved relative to each other so that reflected light from the original may be projected by the copying optical system to form an image on the surface of a recording medium, such as a photoconductive member, rotating at a constant speed. A copy of an original image is then obtained on a copy paper by an electrophotographic process.
However, when printing text and/or images based on stored data, the exposure lamp which operates during the copying operation is turned off and the relative movement between the original table and the copying optical system is stopped. In this condition, an array-type recording unit, such as an LED array, liquid crystal array, or PLZT array, is selectively driven according to the stored data to project an image of the stored data through the recording unit onto the same recording medium used in the copying operation. Thereafter, an image is obtained on the copy paper by the same process used in the copying operation.
However, the following problems are confronted in the conventional recording apparatus.
Specifically, when an electrophotographic process is used, for example, the only difference between the copying function and the stored data printing function is whether the light imaged on the recording medium is reflected light from the original or is light generated according to a stored image. The process after forming the image on the recording medium is common-to both functions. Furthermore, it is necessary to control the photoconductive member rotation and copy paper transport operations so that an image is correctly formed on the copy paper whether the image is a copy or stored image. In the copying operation, these operations are detected by respective detection means to synchronize the relative movement of the original table and the coping optical system. However, during the stored data printing operation, the relative movement of the original table and the copying optical system is stopped in the conventional recording apparatus. Because of this, it is necessary to provide means for detecting the timing in the operation of a recording means in order to control photoconductive member rotation and copy paper transport, making the apparatus more complex and resulting in increased product costs.
Furthermore, while printers effectively print data output from a host computer, they could be even more effectively utilized by providing a facsimile receiver function whereby an image signal received over a telephone line is used as the print data. Unfortunately, while it is easy for the user to control the transmission of print data to a standard printer/copier machine, it is not as easy to control a printer with a facsimile function because an image signal may be sent to the facsimile receiver at any unknown time from a facsimile transmitter in a remote location. The result is complication-of the operations used for copying and for facsimile receiving.
In addition, in the printers, stored data is generally sent out at a relatively high speed whereas the facsimile receivers occasionally receive an image signal sent via the telephone line from a facsimile transmitter of a type having a relatively low transmission speed. In this case, if the recording for the image signal sent from such a facsimile transmitter is performed at a process speed for the copying, the process required for recording the image signal, for example, by one page is completed before all the data for one page are received, thus causing a possibility of data missing.